President Trump tweeted on Wednesday that transgender people cannot “serve in any capacity in the U.S. Military,” repeating a claim from conservative Republicans that transgender service members disrupt the ranks and add medical costs that undermine troop readiness.

Trump made the announcement in a series of tweets,

It’s unclear what impact his decision has on transgender people currently serving in the armed forces. The announcement came on the 69th anniversary of Executive Order 9981, when President Harry Truman signed ending racial discrimination in the US military.

“The full implications of that tweet are to be determined. My read of it is that appears that those currently serving transgender troops will be forced out,” Brad Carson, the Acting Under Secretary of Defense for Personnel and Readiness from 2015-16, who help craft the policy that ended the ban a year ago. “To have a tweet reverse a DoD personnel policy is unprecedented.”

The Department of Defense referred all questions to the White House: “We will continue to work closely with the White House to address the new guidance provided by the Commander-in-Chief on transgender individuals serving the military. We will provide revised guidance to the Department in the near future,” said Naval Captain Jeff Davis, the director of defense press operations.

Secretary of Defense Jim Mattis was on vacation this week and it was not immediately clear whether he knew about the president’s statement before he tweeted it out.

Chelsea Manning, the US Army private first class soldier who was recently released from prison after leaking military intelligence reports, and who transitioned while she was serving her sentence, called the decision “cowardice.”